This invention generally relates to the art of electrical connectors and, particularly, to a method of fabricating an electrical component, such as a metal terminal.
A typical electrical connector includes some form of dielectric housing for mating with a complementary connecting device, such as a mating connector. The housing may be adapted for mounting on a printed circuit board, with a receptacle for mating with the complementary connector, or the housing may receive a second printed circuit board in a board-to-board connection. Whatever the connector configuration, the dielectric housing typically mounts a plurality of conductive terminals or contacts.
An electrical terminal normally includes a terminating portion or end and a contact portion or end. The terminating end is terminated to an electrical wire, a circuit trace on a printed circuit board, a conductor strip on a flat flexible cable or any other conductor of an appropriate electrical device. The contact end of the terminal is adapted for engaging a contact or a contact portion of a terminal of the electrical device to which the connector is mated or interfaced, such as the complementary mating connector. It is highly desirable to plate the contact portion or end of the terminal with a very highly conductive material, such as a precious metal like gold. For obvious cost considerations, the entire terminal preferably is not plated but only the contact portion. In addition, the body or thickness of the terminal is not fabricated of such highly conductive materials as gold, because such materials do not provide the resiliency necessary for most terminals. It should be understood, however, that the invention herein is not limited to electrical terminals and is equally applicable and advantageous for fabricating a variety of electrical components.
With that understanding, some electrical terminals or components are easily plated with the highly conductive material when the contact portions of the terminals are at extreme or distal ends of the terminal configurations. Those ends simply are dipped or immersed in an electrolytic bath to cover the end contact portions, and the precious metal is electroplated on those ends. However, in many applications, the contact portions of the terminals are not at ends or edges thereof, and the dipping process cannot be used. In those applications, a physical masking device is applied to the terminals in areas not to be plated, leaving the contact portions of the terminals exposed. The terminals then are immersed in an electroplating bath, and only the contact portions of the terminals become plated.
Use of such physical masking devices is attended by mechanical wear of the physical masking device and loss of precious plating material due to gaps between the physical masking device and the terminal. Moreover, because each physical masking device is only applicable to a specific range of terminal configurations, a different masking device must be made, maintained and installed into the plating equipment when a plating line is to be converted to plate a terminal from a different range. Lastly, the relatively bulky physical masking devices block the mass transfer of plating material onto the terminal to reduce plating line speed. The present invention is directed to improving the cost effectiveness, precision, speed and versatility of selective plating.
An object, therefore, of the invention is to provide a new and improved method of fabricating an electrical component.
In the exemplary embodiment of the invention, the method includes the steps of providing a metal electrical component and immersing the electrical component in a bath of resist material. A selected area, such as a contact area, of the component is prepared for reception of a conductive plating material. A highly conductive plating material is applied to the selected area. The resist material then is removed from the electrical component.
As disclosed herein, the selected area is prepared by an ink-jet process. The highly conductive plating material is applied in an electroplating bath. The resist material is removed by a solvent, preferably by immersing the plated electrical component in a bath of the solvent.
According to one embodiment of the invention, the selected area is prepared prior to immersing the component in the bath of resist material, by applying to the selected area a masking material which repels the resist material. The masking material is removed prior to applying the conductive plating material. Preferably, the masking material is removed by immersing the component in a bath of rinsing material.
In another embodiment of the invention, the step of immersing the component in a bath of resist material comprises immersing the component in a bath of ultraviolet (UV) curable resist material. The preparing step comprises applying a masking material over the UV curable resist material in the selected area. The unmasked resist material then is cured by using UV rays. The masking material and the uncured resist material in the selected area then are removed prior to the plating step.
In a further embodiment of the invention, the selected area is prepared by removing the resist material in the selected area by a solvent in an ink-jet process.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.